This invention relates generally to radioactive seed implant treatment for prostate cancer, and more specifically concerns a spacer element which is positioned between successive radioactive seeds in a radioactive seed string used in the treatment.
A technique known as transperineal seed implantation, or brachytherapy, has been developed for delivering radioactive seeds to the prostate for treatment of cancer therein. In this technique, a plurality of elongated, hollow needles, each loaded with a series string of radioactive seeds, separated by spacer elements, are inserted into the prostate of the patient.
The loaded needles are accurately positioned within the prostate using ultrasound and a stepper apparatus, in accordance with a pre-planned dosimetry pattern. The needles are then removed, leaving the seeds and spacer string in place in the prostate. This technique, which has been quite successful, is described in more detail in U.S. Pat. No. 6,010,446, by the same inventor as in this application, the contents of which are hereby incorporated by reference.
In the brachytherapy technique, the spacer elements positioned between the successive radioactive seeds play an important role in maintaining the relative position of the radioactive seeds in the series string thereof, both within the needle during insertion and within the prostate after the needle has been removed. The spacer element shown in the ""446 patent maintains the relative relationship between the seeds in the prostate and thus prevents them from migrating within the prostate. While the ""446 spacer element was and is a significant advance over previous spacing arrangements, it is desirable to make the spacer element more user-friendly, i.e. easier to load the seeds therein. It is advantageous to make the process of joining successive radioactive seeds with spacer elements together in a series string of seeds and elements as easy and as fast as possible.
Accordingly, the present invention is a spacer element which is used with radioactive seeds to form a series string thereof, for needle implant treatment of prostate cancer. The spacer element comprises: a spacer element having a central section and two end sections which extend outwardly from the central section, the spacer element comprising two separate portions which are joined by a longitudinal hinge element, such that the two portions come adjacent one another when the spacer element is in a closed position and move apart from one another about the hinge element when the spacer element is moved into an open position, wherein the two end sections are each configured and adapted in such a manner, respectively, to receive and hold a portion of a radioactive seed when the spacer element is in its closed position and to permit convenient loading of radioactive seeds into the respective end sections when the spacer element is in its open position, which thereby permits convenient assembly of a series string of radioactive seeds and spacers; and wherein said string of spacer elements and radioactive seeds is readily fittable within a hollow needle for subsequent insertion into the prostate for use in radioactive seed therapy treatment.